Ceramic Metal Halide Grow Light (CMH) vs HPS – Guide + Review

Ceramic Metal Halide Grow Light (CMH) vs HPS - Guide + Review

An in depth look at CMH bulbs and how they fair against HPS bulbs and other grow systems. We tested a ceramic metal halide bulb for flowering, vegging, and a new prototype LED grow light. We cover the perks and flaws, while running a heat and PAR test.

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What do you think?


Written by Grow Ace

Content AuthorYears Of Membership


  1. I use both a 315W CMH plus an LED right now. Results seem good. Heat that hammers the canopy is still less than a 600W HPS. I like mixing it up in combos. Might try a 400W HPS and the 315W CMH next run.

  2. Hps for YIELD cmh for Quality. Make your choice on what you are looking for but please if someone or a shop is telling you a CMH matches hps for yield ignore them as they are either a bad grower not maximising the potential of their hps OR are try to make money from you by pushing products on you.
    Your welcome

    Seasoned grower of many fruits and vegetables 😁 over 17 years….. and still learning.


    THANK ME LATER !!!🍾🍾🍾🍾💰💰💰💰💰💰💵💵💵💸💸💸

  4. I'm running 3 double ended 600watts cmh . the 3 don't put off as.much heat as 1 de 1000watt hps mh . everything about it is better. Leds aren't worth the money yet! They are getting better but no comparison to cmh.

  5. I have two phantom cmh315's and they work great. Got 5 ozs off of one plant once. Depending on the genetics and how well they are taken care of, you can expect 3 to 5 ozs per plant in a 4×4 tent with one cmh315. I like to use two lights for cross penetration in a 4×6. Plants also grow at an angle with only one light. Plus, HPS lights are wasting electricity producing colors of light that the plant doesn't need.

  6. Doesn't make much sense, and you contradict yourself at the end, 7:35, saying that a cmh bulb is equivalent to an hps? Your own tests show that that is not true! Look at the chart with your par numbers..the hps is considerably better than the single cmh, so why do you say its better at the end? Then you say it's half the cost? No it's not, a 315 cmh is twice as expensive as a 600 watt hps setup! As for temps, again, your own test showed the hps to be 16 degrees hotter and the cmh at 12..not much of a difference there! This video is all over the place, and you seem confused as to what you are trying to demonstrate!

  7. With hps there is the photon flux field density it has more penetration as growers know this would be photon field density. HPS is designed to push through fog in street lighting it has punch in the canopy. This is an area that is often ignored in comparisons this idea of claiming par on hps is bs as growers know. CMH would make a good addition to hps spectrum improving the cri and UV A why not use both? I use led to side light with hps it also peaks the 660 nm but IMHO photon flux density is an area ignored in comparative marketing the claims that various lights are par with hps is complete bs in my experience. HPS get the fat flowers but combining other spectrums with say led or cmh is working for me. CMH are efficient and good spectrum and UV A but HPS DE still sets the benchmark IMO

  8. Hps shits all over these lights yield wise, my friend has ran both, he got 7 ounces off a plant under a 630 double, and 11 ounces off a 1000 Hps, yet these idiots try to tell you the 630 is equivalent to 1000 Hps

  9. At 734 you Lied you said the 315 cmh has more lighting then the 600watt Hps which you admitted in the test and the comments is no where NEAR TRUE, its WAY LESS PAR OUTPUT

  10. So the dual cmh is useless you are saying the heat makes the 630 dual comparable to 1000 hps BUT CMH ACTUALLY GETS HOTTER with LESS PAR so it has to go further away with LESS LIGHT OUTPUT…

  11. This video is dishonest n biased trying to sell cmh.
    They try to say a 315 cmh is worth a 600 hps in light intensity its not even close..
    Shop tried to sell me a 630 double saying it will give same yield as 1000 hps not EVEN CLOSE.Good for Quality not yield.
    At that price why buy a 630 cmh when its only comparible to 600 hps, and when they talk heat, remember plants like heat, which is also easily controllable with good airflow..

  12. I've never seen any of the top breeders producing the best cannabis use anything other than HPS and MH. Not talking about the new commercial growers. When I see these guys using something different is when I'll switch I think.

  13. 2:19 "315W CMH is stated to produce far more par then a 600w hps."
    4:26 The PAR charts show the 315W CMH producing far less PAR then the 600W HPS.
    Why the discrepancy? Were you referring to PAR per watt?

  14. How do people move around a grow room that has plants right through it?
    I mean, I've seen rooms completely filled with Cannabis and SCROGed, besides!
    How do they manage to get in between the plants to properly scrog/trim/etc.? Something I've always scratched my head at.


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